Moscow: Prominent Azerbaijani rights activist Leyla Yunus and her husband went on trial Wednesday on charges of committing economic crimes that the couple say are politically motivated.

During the first hearing in Baku`s grave crimes court, prosecutors accused Leyla and Arif Yunus of crimes including illegal entrepreneurship and tax evasion, an AFP journalist reported from the courtroom.

If found guilty, they could face a jail term of up to 12 years.

Arrested last year on suspicion of spying for arch-foe Armenia, the couple also face charges of treason in a separate case.

"Leyla Yunus insists that she is being persecuted because of her rights campaigning," her lawyer Elchin Gambarov, told AFP.

"She rejects all the charges as absurd and politically-motivated."

The lawyer said Leyla Yunus is suffering from several serious illnesses, including liver necrosis and "with her health irreversibly deteriorating, she may die in custody."

The Yunuses` lawyers have petitioned to end the couple`s prosecution as unfounded or to release them on bail, citing their poor health.

But a judge at the Baku court has rejected both motions and refused to give Leyla Yunus the floor during the latest hearing.

"You are depriving me of my right to speak, you don`t respect the law," Leyla, who looked pale and emaciated, told the judge.

"They want us to die in prison," she said.

Yunus also alleged that she has been regularly beaten by prison guards in a pre-trial detention centre.

Western governments and human rights groups have expressed strong concern over the Yunuses` prosecution.

Human Rights Watch has denounced their case as a "show trial", and Amnesty International says they are prisoners of conscience.

"The trials against many of the dozens of (Azerbaijani) government critics targeted in the sweeping crackdown of the past few years also bode poorly for a fair hearing for Leyla and Arif," Rachel Denber of New York-based Human Rights Watch said on Sunday.

Leyla Yunus, 59, heads one of Azerbaijan`s leading rights groups, the Institute for Peace and Democracy, in the capital Baku.

She has won several international awards for her work, and has teamed up with Armenian activists to urge reconciliation between the two countries, locked in a decades-long conflict over the disputed Nagorny Karabakh region.

Dissent in tightly-controlled Azerbaijan is often met with a tough government response.

Rights groups say the government of the oil-rich ex-Soviet republic has stepped up pressure on opponents since President Ilham Aliyev`s election for a third term in 2013.